Embodiments of the present specification relate to sensors, and more particularly to wireless sensors.
Typically, harsh operating conditions may be present in an interior of an internal combustion engine or on a moving blade of a gas turbine. Non-limiting examples of these harsh operating conditions may include high operating temperatures, high operating pressures, dynamic motions, or combinations thereof. Generally, in operation, it is desirable to monitor one or more environmental parameters in devices and systems operating under the harsh operating conditions. These environmental parameters may include one or more of temperature, pressure, velocity, vibrations, acceleration, or humidity.
Gas turbine engines are examples of devices within which extremely harsh operating conditions may prevail. Further, the gas turbine engines may be used for various purposes, including propulsion and power generation, which typically experience the harsh operating conditions. A typical gas turbine engine includes rotating and non-rotating components, such as the compressor, combustor and turbine sections of the engine. Each of these components may operate in a different temperature range. For example, in the turbine section of a gas turbine engine, the turbine blades may be exposed to gases which may reach temperatures from about 1000° C. to about 2000° C. Due to concerns pertaining to corrosion, mechanical degradation, and thermal degradation it is desirable to monitor temperatures of components employed in the gas turbine engines and other devices operating under the harsh operating conditions.
Different techniques may be used to monitor a surface temperature of blades, vanes, combustors, discs, and the like. in the gas turbine engines. Non-limiting examples of these techniques may include wire thermocouples, thin film thermocouples, infrared photography, pyrometry (for example, three-dimensional pyrometry), thermo-graphic phosphors and thermal paints. A common technique used in the aircraft engine environment employs thermocouple wires embedded in the blade or vane wall. However, embedding wires in the walls may cause structural and aerodynamic complications, including perturbing the flow of air that is used to cool the blades and/or the vanes. This perturbation in the flow of air may affect a boundary layer of air present next to the blade or the vane and may adversely impact turbine performance. Further, another embedded thermocouple technique, employs plasma sprayed alumina ceramic coatings to encapsulate and insulate small diameter thermocouple wires on blades and vanes. However, due to the thermal mass of the wires and associated ceramic insulator layers, such devices may introduce measurement errors.